Electronic devices, for example, a processing unit for executing a sequence of logical operations, are widespread. It is desired to use similar electronic devices with different applications to reduce the provided overall number of different electronic devices. For this purpose, it is necessary to adapt the electronic device to the different applications by setting its mode of operation. Setting the mode of operation may comprise the adaption of the electronic device to different periphery devices and/or periphery device configurations that may be connected to the electronic device, for example.
The setting of the mode of operation may be based on the previous detection of an intended mode of operation for the electronic device. When the setting of the mode of operation is completed, the electronic device is configured. It is useful to realize the setting of the mode of operation in hardware so that it is software independent, guarantees a known default state, and complies with safe requirements.
Common electronic devices usually comprise a plurality of pins that provide an electrical interconnection between the electronic devices and the periphery devices. In order to adapt an electronic device to different periphery devices and/or different periphery device configurations, it is known to detect a size of an external resistor connected to one of the plurality of pins.
In addition, it may be desired to use the configured electronic device in a debug mode for development purposes. In order to control the activation of the debug mode of a configured or unconfigured electronic device, it is known to use a pin that is different from the pin used for configuration. However, the cost of the electronic device increases with the total pin number.
In order to reduce the total pin number, the U.S. Pat. No. 5,557,236 describes the alternate use of a single pin as an input pin and an output pin. U.S. Pat. No. 6,499,123 describes the different use of a single pin depending on its mode of operation.